Pharmacologic and genetic methods are being used to determine the psychobiological mechanisms underlying various behavioral processes. The current research is focused on the neurobiology of anxiety, impulsivity and aggression in mice and on learning and memory processes in humans. The effects of ethanol, and of drugs with known and specific mechanisms of action are being investigated. Selective alpha-2 adrenoceptor antagonists have been shown to reduce ethanol's hypothermic and ataxic effects but not to alter ethanol's anxiolytic, anticonvulsant or locomotor stimulant effects. The effect is mediated centrally rather than peripherally and appears to involve alpha-2 adrenoceptors rather than imidazoline binding sites. Male mice that show high levels of aggression towards their cage-mates differ from both their subordinate cage-mates and from control mice housed in cages in which little fighting is observed. The most consistent difference is observed in Porsolt's swim test where subordinate mice show increased immobility relative to controls. The behavioral differences appear to follow rather than precede the aggressive social interactions.